Fluid compressor



June 25, 1929. G. HILGER FLUID COMPRESSOR Filed Nov. 28, 1927 2 Sheets-Sheet G. HILGER June 25, 1929.

FLUID COMPRESSOR Filed NOV. 28, 192'? 2 Sheets-Sheet 2 Patented June 25, 1929.

UNITED STATES GEORGE HILGER, OF CHICAGO, ILLINOIS.

FLUID COMPRESSOR.

Application filed November -2s, 1927. Serial No. 236,076.

The present invention relates to improvements in compressors for fluids, such as ammonia, and has particular reference to a novel compressor adapted to handle a plurality of fluids having different back pressures.

In refrigerating systems, spent ammonia from diflerent cooling devices may be returned to the compressor at differentpres sures. The primary object of the present invention resides in the provision of a novel twin cylinder compressor which will handle fluids from different sources with as many as four different respective back pressures.

A further object resides in the provision in a twin cylinder compressor of novel means for separating opposed cylinder ports and connecting said ports to independent inlet trunks or pipes.

Further objects and advantages will become apparent as the description proceeds.

In the accompanying drawings, Figure 1 is a side elevational view of a compressor em; bodying the features of my invention.

Fig. 2- is a plane view.

Fig. 3 is a detailed view in elevation on one of the partition sleeves between the opposed cylinder ports.

Fig. 4 is a fragmentary sectional View taken along line 4-4 of Fig. 6.

Fig. 5 is a fragmentary vertical sectional View taken along line 55 of Fig. 2.

Fig. 6 is a horizontal sectional view taken along line 66 of Fig. 5. v

Fig. 7 is a horizontal sectional view taken along line 7-7 of Fig. 5.

IVhile the invention is susceptible of various modifications and alternative construc tions, I have shown in the drawings and will herein describe in detail the preferred embodiment, but it is to be understood that I do not thereby intend to limit the invention to the specific form disclosed, butintend to cover all modifications and alternative constructions falling within the .spirit and scope of the invention as expressed in the appended claims.

Referring more specifically to the draw ings, the exemplary embodiment of the invention consists of a compressor 10 which is adapted to receive fluid from four different sources normally under different back pressures. To this end, the compressor 10 is connected to four separate inlet pipes 11-12 la 14 leading to difierent scurces (not shown), such as cooling" devices employing ammonia as the refrigerant.

The compressor 10 comprises twin cylinders 1516 in which suitable pistons 17-18 respectively are slidably disposed. In the present instance, the outer or upper ends of the cylinders 15-16 are suitably closed by means of a removable head 19, and the inner ends thereof open to a crank case 20. Suitably j ournaled in bearings 21 in the ends of the case and projecting from the latter is a crank shaft 22 which is adapted to be driven by any suitable means, such as the pulley 23, and the throws of which are spaced angularly 180. The throws of the shaft 22 are operatively connected to the inner ends of the pistons 1718 by means of connecting rods 2 125.

The cylinders 1516 are each provided with two longitudinally spaced inlet means designated respectively at 2627 and 28-29. Preferably, each inlet means comprises a set of closely spaced ports formed in the wall of the cylinder. The two sets of inlet ports 2628 are directly opposed and open respectively to the upper ends, conveniently designated as high pressure chambers 30-31, of the cylinders 1516; and each set of ports is so located that it will be just uncovered when the associated piston is in its innermost position. The two sets of inlet ports 27-29 are also directly opposed and open respectively to the cylinders 15-16 about the pistons 17-18 and communicate at all times with the interior of the pistons, conveniently designated as low pressure chambers 3233. To this end, each of the pistons 1718 is formed in its lower end with a peripheral space com.- municating with the associated set of ports in all positions of reciprocation of the piston. These spaces, designated as 34-35, communicate through large openings 3637 with the chambers 3233. I

Suitable valves 3839 are provided respectively in the upper ends of the pistons 17 18 between the high and low pressure chambers. In the present instance, these valves are alike, and hence only one of the valves will be described. Each valve comprises a suitable beveled valve plug 40 adapted to rest against a valve seat 41 during the compression stroke of the piston and to be raised from said seat during the suction stroke of said piston. The seat 1H. famed at the u per end of a bore It will be evident that when the pressure 111 the low pressure chamber is higher than that in the high pressure chamber, the valve will be open, and when. the opposite condition obtains the valve will be closed. As will be apparent hereinafter, the first mentioned condition obtains during most of the suction stroke and until the upper set of inlet ports is uncovered, and the last mentioned condition obtains during the compression stroke.

The inlet ports 26272829 are connected respectively with the pipes 1112 12)1 1; These pipes receive exhaust fluid, such as ammonia, from diii'crent sources (not shown) discharging the fluid at different pressures. F or illustration, let it be assumed that there is ammonia at 6 F. and a gauge pressure of 10 pounds per in. in the pipe 12; ammonia at -50 F. and ZOI'O gauge pressure in the pipe 14:, ammonia at 3 1 F. and a gauge pressure of 50 pounds per in. in pipe 11, and ammoniaat 18 F. and a gauge pressure of 30 pounds per in. in pipe 13.

Opening through a web 19 between the cylinders l516 are two bores 5051. The bore 50 communicates at opposite sides through passages 52-53 with the two upper sets of ports 26-28; and the bore 51 communicates at opposite sides through passages 5i-55 with the two lower sets 01: ports 27 29. Rigidly disposed in the bores 5051 respectively are two cylindrical sleeves 5657 formed re spectively with inner diagonal dividing or partition walls 5859 separating the opposed cylinder ports. G1 the sleeve 56, the opposite ends are formed with ports 6061 respectively opening to the passages 52-53. Similarly, the opposite ends of the sleeve 57 are formed with ports 6263 respectively opening to the passages 5 155. The discharge ends of the pipes 1112131+t are secured to the web 49 and end to end withthe sleeves 56-57 by any suitable means, such as the littings 64.

The low pressure inlet pipes 121l are connected by a shunt or by-pass pipe 65 in which a suitable valve 66 is interposed. Similarly, the high pressure inlet pipes 11 13 are connected by a bypass pipe 67 in which a suitable valve 68 is interposed. in the present instance, the valves 6668 are alike in con- Si111Ct1011,111Cl hence but one will be described in detail. Preferably, each of the valves 66-68 comprises a valve fitting 69 having a valve seat- 70 facing the high pressure line. A valve member 71 is pivotally mounted in the fitting 69, and normally is held by the pressure difl'erential against the seat 70. It will be evident that it the pressure in the pipe to the rear 01 the seat 70 should rise above that in the other pipe, the valve will open, thereby automatically equalizing the pressure in the two pipes and admitting fluid in eliect from a single line to both cylinders.

The cylinders 15 16 are provided respectively with suitable fluid discharge means 72-73. In the present instance, these two means are alike, and therefore only one will be described.

Each of the means 72- 0 comprises a floating valve piston 741 slidably disposed in the upper end of the cylinder which is slightly enlarged to form a beveled seat 75. The piston 7 1 normally rests against the seat 75, in which position it covers 21. pl urality of discharge ports 76. Disposed between the head 19 and the piston 74: is a heavy coil spring 77 which tends to hold the piston in position when the pressure in the cylinder is below a predetermined maximum, but which will permit a pressure relief past the seat when the pressure rises above said maximum. The piston 74 is "formed with an inner chamber 78 opening through ports 79 to the cylinder and through ports 80 to the discharge nuts 7 6. A suitable ieldinemem her 81 overlies the ports 79, and serves to close the latter during the suction stroke, and

at all times when the discharge pressure is higher than the pressure in the cylinder. The discharge ports 76 from the two cylinders 15 16 open into a single high pressure pipe line 82. In practise, a pressure of approximately 180 pounds per in. may be maintained in the line 89..

In; operation, the lines 11121314 may receive exhaust fluid, such as spent ammonia from diiicrent cooling systems, at different pressures, for example 50 pounds, 10 pounds, 30 pounds, and 0 pounds, gauge pressure per i119. The compressor will take the fluid from these lines and compress it to a desired predetermined discharge pressure, for example 180 pounds per, in. Referring to Fig. 6, the interior of the piston 17 is constantly filled with fluid from the pipe 12. As the piston 17 moves downwardly on the exhaust stroke, the valve 72 will be closed, and the valve 38 will be opened to fill the high pressure chamber 30 with fluid from the pipe 12. The pres sure in the chamber 30 at this time will be 10 pounds per inF. lVhen the piston 1? uncovers the ports 26, the valve 38 will be closed, and the high pressure chamber 30 will receive additional fluid from the pipe 11 to raise the pressure in the chamber to 50 pounds per in. ()n the compression stroke of the pisten. the fluid in the chamber 30 is compressed and discharged through the valve 72 to the pipe 82. A similar cycle takes place in the cylinder 16. Thus the chamber 31 is first filled with fluid at a gauge pressure of 0 pounds persquare in. from the pipe 14, and then with additional fluid at a pressure of 30 pounds per square in. from the pipe 13.

It will be'eviden't that the compressor 10 when operating in the above manner thus conveniently handles fluids with four different back pressures.

If the valve '66 is open, the pressures in the pipes 12 and 14 will equalize, and fluid of the same pressure will enter through the ports 2729. It the valve 68 is open, the pressures in the pipes 1113 will equalize, and fluid of the same pressure will enter through the ports 262S. In each of these events, the compressor will be handling fluids with three different back pressures. If both valves 6668 are open, the compressor will be handling fluids with two different back pressures. By providing the valves 6668, it will be evident that if the pressure in the pipe 11 falls below that in the pipe 13, as for example when the supply of fluid to the pipe 11 is cut off, fluid from the pipe 13 will enter the pipe 11 so as to fill the chamber 30 with high pressure fluid. Under similar circumstances, fluid from the pipe 14 will enter the pipe 12 so as to fill the chamber 32. Hence, the compressor will still take in fluid through the four inlets, thereby resulting in efiiciency. In practice, the pipes 13 and 14 are usually connected to fairly constant sources of spent fluid, and the pipes 11 and 12 may be connected to fluctuating or intermittent sources. \Vhen desired, the valves 66 and 68 may be opened manually without regard to the pressure differentials.

I claim as my invention:

1. A comprsesor having, in combination, two cylinders, each cylinder having a high pressure inlet and a low pressure inlet, the high pressure inlets and also the low pressure inlets of said cylinders being in opposed relation, a plurality of inlet pipes one for each inlet, and means comprising a partition wall between each pair of opposed inlets, said means connecting the latter respectively to said pipes.

2. A compressor having, in combination, a pair of cylinders, two pistons one reciprocable in each of said cylinders, two opposed inlet means opening respectively to said cylinders and adapted to be uncovered by said pistons, a sleeve having ports opening respectively to said inlet means and having a partition wall between said ports, and two fluid supply pipes opening respectively to opposite ends of said sleeve.

3. A compressor having, in combination, a pair of spaced cylinders, a pair of pistons one reciprocable in each cylinder, low pressure inlet means automatically operable to admit fluid to said cylinders during the suction stroke, high pressure inlet means adapted to be uncovered near the end of the suction stroke to admit additional fluid to said cylinders, means for supplying pressure fluid separately to each inlet means for each cylinder, and means for connecting said low pressure inlet means and also said high pressure inlet means when the occasion arises.

1. A compressor having, in combination, two cylinders each having two separate inlet means, said inlet means for said two cylinders being arranged in opposed relation to form pairs, two partitions one between the opposed inlet means of each pair, and four supply pipes, one opening to each inlet means.

5. A compressor having, in combination, a pair of spaced cylinders, a pair of pistons one reciprocable in each cylinder, low pressure inlet means automatically operable to admit fluid to said cylinders during the suction strokes, high pressure inlet means adapted to be uncovered near the end of the suction strokes to admit fluid to said cylinders, and means for supplying pressure fluid separately to each inlet means for each cylinder.

- 6. A compressor having, in combination,

two cylinders each having two spaced inlet means for admitting fluid at different times, said inlet means for said two cylinders being arranged in opposed relation to form pairs, two partitions one between the opposed inlet means of each pair, inlet pipes, one opening to each inlet means, a by-pass pipe connecting the inlet pipes for each pair of inlet means, and a valve in each by-pass pipe.

7. A compressor having, in combination, a pair of cylinders, two pistons one reciprocable in each of said cylinders, two opposed inlet means opening respectively to said cylinders, an inlet passageopening to said inlet means, a diagonal partition wall in said passage between said ports, and fluid supply pipes opening to said passage respectively at opposite sides of said partition.

8. A compressor having, in combination, a pair of cylinders, two pistons one reciprocable in each of said cylinders, two opposed inlet means opening respectively to said cylinders, a sleeve having openings communicating respectively with said inlet means and having a diagonal partition wall between said openings, two separate supply pipes opening respectively to said sleeve at opposite sides of said partition wall, a pipe connecting said supply pipes, and a valve interposed in said last mentioned pipe.

9. A compressor having, in combination, a pair of cylinders, two pistons one reciprocable in each of said cylinders, two" opposed inlet means opening respectively to said cylinders, a sleeve having openings cominunicating respectively with said inlet means and having a diagonal partition wall between said openings, two separate supply pipes opening respectively to said sleeve at opposite sides of said partition wall, a pipe connecting said supply pipes, and a valve interposed in said last mentioned pipe, said valve being responsive to the pressures in said supply pipes to close When the pressure in one of said pipes is in excess and to open When the pressure in said one pipe is not in excess of the pressure in the other pipe.

10. A compressor having, in combination, a pair of cylinders, two pistons one reciprocable in each of said cylinders, tWo inlet means one opening to each of said cylinders,

two fiuid supply pipes one connected to each 10 of said inlet means, a plpe connecting said two pipes, and a valve interposed in said last mentioned pipe.

In testimony WhereoijI have hereunto aiiixed my signature.

GEORGE HILGER. 

